dauphin island’s east end beach and barrier island...
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Dauphin Island’s East End Beach and Barrier Island Restoration Project
Town of Dauphin Island, AlabamaTown of Dauphin Island, Alabama
April 16, 20156:00 PM
Dauphin Island Sea Lab, Shelby Hall
“Team” Introduction
South Coast Engineers
Coastal TechCoastal Tech
Hutchinson Moore & Rauch
Purpose of Presentation
Describe the proposed project:
Design Development: Overall Project Steps
• Research/Understand Site History & Coastal Processes
• Develop Working Project Goals• Prepare Conceptual Design(s)• ‘Recon’ and Final Borrow Area Investigations• ‘Recon’ and Final Borrow Area Investigations• Begin Regulatory Process• Finalize Design Work• Complete Permitting > Final Plans &
Specifications• Establish Mean High Tide Line & Conclude
other Easements• Bidding, Construction, Monitoring
Design Development: East End Coastal Processes
Beach erosion on eastern mile of beaches is influenced by position/elevation of Pelican and Sand Island shoals
Design Development: Historic Erosion Rates
• From 2005 (Katrina)-2010 beach retreated at rate of 8.4 ft/yr (40+ feet). Equates to about 220,000 cu yds of erosion.
• From 2010-2013 another ~50,000 cu ydsFrom 2010-2013 another ~50,000 cu yds
• Long-term
land loss
evidenced by
position of
old rock groins
Design Development: Project Goals
• Restore and protect wildlife habitats on the east end including Gulf-front foraging and nesting habitats for seabirds, shorebirds, neotropical migratory birds, and sea turtles
Reduce risk of saltwater intrusion into the • Reduce risk of saltwater intrusion into the freshwater lake in bird sanctuary
• Introduce beach sands into the littoral drift of the Gulf barrier island
• Increase longevity of new sand by concurrent use of rock breakwaters
Design Development: Borrow Area
• Recon looked at western flank Mobile Bay ebb tidal delta
• Final investigation sought to identify a sub-area:
– (1) is most proximal to the fill – (1) is most proximal to the fill Project Area,
– (2) avoids cultural resources to the maximum extent possible, and
– (3) contains sufficient sand quantities with a factor of safety of at least 2 (sub-area volume is 600,000 cubic yards).
• Borrow sub-area as requested in permits
• No indication in any of field work of contaminants
• Laboratory testing • Laboratory testing of proposed Borrow Area sand compared to Native Beach
Sample
gINT Granularmetrics
USC
Munsell Color
Size Class (wt%) Descriptive Statistics Wet Dry
Gravel Sand <#200 <#230 Mean (mm) Verbal Std. Dev.(phi) Value Chroma Value Chroma
CTC Native 0.72 98.8 0.48 0.47 0.28 F 0.76 SP 6 3 8 2
CPE Native^ 1.09* 98.57 0.34 0.33 0.28 F 0.82 SP 6 2 7 2
CPE + CTC Native 0.71 98.86 0.43 0.42 0.28 F 0.79 SP 6 3 7 2
Sub-Area 2 0.27* 98.31 1.42 1.4 0.26 F 0.65 SP 6 1 7 1
Project Description - Funding
Funded through the State Lands Division of the Alabama Department of Conservation and Natural Resources
Coastal Impact Assistance Program Coastal Impact Assistance Program
(AL-28: Dauphin Island Shoreline Stabilization Project)
Project Description –Introduce New Sand by Beach
Nourishment
Features:
~300,000 cubic yards of beach fill concentrated
Beach nourishment:
The placement of beach fill concentrated behind renovated rock structures and extending west to near the west side of the bird sanctuary
The placement of large quantities of good quality sand
directly on the beaches to restore the
beach.
Project Description – Beach Nourishment
Project Description – Concurrent Use of Rock Structures
Existing rock groins to be renovated as offshore segmented breakwaters
Will include reinforcement with new, heavy armor stone
Will increase the longevity of the sand near the road end
State Regulatory Agencies
• Alabama Department of Environmental Management (ADEM)
State Permitting
• AL Department of Conservation & Natural Resources, State Lands Division (ADCNR)
• Alabama State Historical Preservation Commission (SHPO)• Tribal Authorities
State Permitting Process
ADEM’s Administrative Code requires that all permitted projects:
• Meet state water quality standards
State Permitting
• Meet state water quality standards• Utilize only quality fill material• Are consistent with the AL Coastal Area
Management Program• Do not impact submerged cultural resources• Include mitigation for project impacts, if
warranted
Pre-application meeting held October 30, 2013
ADEM-COE Joint Application submitted March 12, 2014
State Permitting
Responses to ADEM’s requests for clarification and/or additional information
ADEM permits issued on October 3, 2014• Coastal Consistency Certification• Water Quality Certification
• Implementation of Post Construction Monitoring Plan• Project Completion Certification• Turbidity monitoring during construction• Topographic/bathymetric surveys of beach
• 90 days prior to construction• 60 days following construction• Annually for 3 years
• Bathymetric survey of borrow area• 90 days prior to construction (or prior survey)
ADEM Required Monitoring/Submittals
• 90 days prior to construction (or prior survey)• 60 days following construction
• Engineering report with monitoring data within 90 days of each post construction and annual monitoring survey
• Aerial photography• Immediate post construction• Year 1 post construction
• Lighting surveys/report• Year 1 post construction – 2 surveys
• Sea turtle monitoring/reports • 2 nesting seasons post construction
• Tilling/escarpment surveys• Prior to May 1 for 3 years post construction
The National Environmental Protection Act (NEPA)• Requires federal agencies to integrate environmental issues into their decision making
process
Section 404 of the Clean Water Act• Regulates the discharge of dredged or fill material into waters of the state
Section 10 of the Rivers and Harbors Act of1899
Federal Permitting Process
Section 10 of the Rivers and Harbors Act of1899• Regulates construction of any structure in or over navigable waters of the United States
Commenting agencies:• Alabama Historical Commission, State Historic Preservation Officer (SHPO)
• Preservation of non-renewable cultural resources
• U.S. Fish & Wildlife Services (FWS)• Protection of listed species under the Endangered Species Act
• National Marine Fisheries Service (NMFS)• Implementation of Terms & Conditions for dredging offshore areas within the Gulf
of Mexico Regional Biological Opinion (GRBO)• Tribal Authorities
• Preservation of Tribal cultural resources
Responses to requests for clarification and/or additional information
USACE permit issued 12/4/2014
Federal Submittals
USACE permit issued 12/4/2014
SHPO concurrence issued 8/11/2014
• Construction may occur year round• Pre-construction meeting with agencies, contractor monitors, surveyors,
Town representatives• Sea turtle monitoring/reports
• during construction (if construction occurs between May 1 and September 30) and 2 nesting seasons post construction
• Use of beach quality sand free of contaminants• Installation of predator-proof trash receptacles
Provide U.S. Coast Guard Notice to Mariner
Federal Requirements/Submittals
• Provide U.S. Coast Guard Notice to Mariner• Compliance with National Flood Insurance Program• Endangered species monitor during dredge operations• Dredge Quality Management operational during all dredging• Turbidity monitoring during construction• Notify USACE and SHPO if cultural resources are found• Immediate post construction summary report to USFWS• Tilling/Escarpment Surveys
• immediate post construction and annually for 3 years
• Lighting surveys/Report• year 1 post construction
Required Easements and Conveyances
Dauphin Island Park and Beach Board and Dauphin Island Sea Lab have signed easements
United States Coast Guard has provided a construction staging area license and will be providing a conveyance agreement (equivalent to these easements for federal lands)
Mean High Tide Line
Establishment of a line is required by state law before construction of a beach restoration projectbeach restoration project
Established by a public hearing with associated map or documentation
Mean High Tide Line
MHT line as surveyed as it existed in January 2010
Adopted by the Town Council at public Adopted by the Town Council at public hearing May 7, 2014
To be established only for the specified project area
Mean High Tide Line
Project LimitsCCCL 2010 MHT Line
Mean High Tide Line
Title to filled land lying seaward of the “designated” MHT line is retained by the state
Affected landowners retain all “statutory and common-law riparian or littoral rights of access” to the filled land, “subject to reasonable regulation” by the Town.
Next Steps
ADCNR/ADEM receives public input (tonight!)
Permit issuance decision by ADCNRPermit issuance decision by ADCNR
Bids & Construction (this spring/summer)
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